A lot of times, a systematic change requires more effort than that. The working may have helped. It may have worked. Your own determination to make sure your desired outcome happens, though, is up to you. A spell cannot change you; it can help you change yourself.
Changing a long-term habit or behavior, a chemical dependency, or emotional dependency, does not typically happen in a day. It has for some, and so I will not say that it cannot change in an instant.
As for emotional changes, they can take even more effort.
Regression is also a risk, which is partly why this effort will require continuous determination.
A friend of mine, for example, is a (I like to say former, but she says recovering) addict. She has been clean for years, and does not seek the things she used to do. However, her life is very strict in that regard: She does not allow a lot of things into her home, such as alcohol or tobacco, because she does not want the temptation to even exist where she lives. She does go out with friends, and does not partake in any intoxicant. She even avoids a lot of prescription medications, for concern of a relapse.
Was her recovery related to magic? I would have to say yes. She made some major changes -- and changes that are not easy.
You did it right, but with any addictive thing that you are trying to quit, you will probably have to do the spell regularly. Just to get it jammed into your subconscious.
I quit cigarettes with hypnosis, it has been about 10 years now, but I know that I could go back to them in a heartbeat. It's all about the Will.